1. Field of the Invention
The invention is generally related to a new class of compounds identified as arylethynyl phthalic anhydrides. In addition, the invention is directed to polymers having pendant or terminal amines that are reacted with arylethynyl phthalic anhydrides to produce a high performance/high temperature resin having superior solvent resistance, heat resistance, and toughness properties.
2. Description of the Prior Art
There is a growing demand for thermosetting polymers that are processable, yet solvent resistant, and can withstand temperatures temperatures in excess of 700.degree. F. (371 .degree. C.) for extended periods of time. Including an endcapping or pendant group at the end of a polymer chain or along the backbone of the polymer, respectively, which is capable of crosslinking or chain extension at high temperatures can provide a thermoset which has highly desirable solvent resistance and toughness properties. A chief requirement for the endcapping group or pendant group is that it not cure (e.g., undergo the crosslinking reaction) until after the onset of flow of the polymer. That is, the endcapping or pendant group must have a higher cure temperature than the melt temperature, T.sub.m, and/or glass transition temperature, T.sub.g, of the polymer. Presently available nadimide, maleimide, cyanate, and acetylene end cappers do not fit this criteria for many high performance/high temperature polymeric materials. Specifically, many high performance/high temperature polymeric materials have T.sub.g 's that are higher than the cure temperature for these end cappers.
Recently, many laboratories have found that substituted ethynyl compounds are useful as plasticizers, endcappers or pendant groups. These compounds undergo addition reactions at high temperatures, thus they may allow the formation of heat and solvent resistant high performance/high temperature thermosets. For example, U.S. Pat. No. 4,131,625 to Arnold et al. discloses the use of 4,4-bis(3-ethynylphenoxy) diphenylsulfone as a plasticizer prepared from 3-ethynylphenol. U.S. Pat. No. 4,128,588 to Sabourin discloses the preparation of a nitrophenyl hydroxy substituted acetylene for use as an endcapper. Paul et al., Abstracts of the IVth International Conference on Polyimides, Ellenville, N.Y., 1991 discloses the use of 3-phenylethynyl aniline (PEA) as a high temperature curing endcapper. Jayaraman et al., Polymer Preprints 34, Mar. 1, 1993, p. 511 discloses the synthesis of 3-phenylethynyl phenol for use as an end capper to high temperature arylene ethers. Jensen et al., Polymer, 34:630-635 (1993) discloses the synthesis of polyimides with pendent ethynyl groups. Sabourin et al., J. Org. Chem., 48:5135-5137 (1983) discloses the synthesis of 4-ethynylphthalic anhydride via 2-methyl-3-butyn-2-ol, but does not describe its utility.